Power-driven hacksaw



D. L. CHANDLER POWER Aug. 17, 1954 -DRIVEN HACKSAW 5 Sheets-Sheet 1 Filed Jan. 27, 1950 1954 D. L. CHANDLER POWER-DRIVEN HACK-SAW 3 Sheets-Sheet 2 Filed Jan. 2'7', i950 D. L. CHANDLER POWER-DRIVEN HACKSAW Aug. 17, 1954 3 Sheets-Sheet 3 Filed Jan. 27 1950 Patented Aug. 17, 1954 UNITED STATES OFFICE POWER-DRIVEN HACKSAW Application January 27, 1950, Serial No. 140,830

1 Claim.

This invention relates to an improved power driven tool of the hacksaw type, in which a hacksaw blade, or similar cutting element, is arranged to be reciprocated while in engagement with a work piece positioned and held in the path of movement of the cutting element.

It is an object of the invention to improve a power driven tool of the class indicated and to devise a simple, compact, and durable hacksaw arrangement which is especially designed to be driven by standard types of electric hand drills. It is a further object of the invention to provide a cheap and efiicient hacksaw which is easily set up for use either in a bench vise or in some other convenient manner; which can be easily operated with a minimum amount of adjustment; and which is constructed from a relatively small number of working parts.

These and other objects and novel features will be more fully understood and appreciated from the following description of a preferred embodiment of the invention selected for purposes of illustration and shown in the accompanying drawings, in which Fig. 1 is a plan view of the tool of the inven tion shown in engagement with a work piece held at the right-hand side of the figure;

Fig. 2 is a side elevational view of the device;

Fig. 3 is another elevational view illustrating an opposite side of the device;

4 is an end elevational view of the forward extremity of the tool;

Fig. 5 is a cross-section taken on the line '55 of Fig. 2; and

Fig. 6 is another cross-sectional view taken on the line 6-5 of Fig. 2.

In the structure shown in the drawings, numeral It refers to a frame of rectangular shape and constituting a four-sided enclosure open at its top and bottom. Within this enclosure is contained mechanism for controlling the move-- ment of the saw, including driving means; saw reciprocating mechanism; and a rocker motion, as well as work holding apparatus for positioning a work piece in the path of movement of the saw. Outside of the frame it! and in spaced relation to one of its side walls is a blade holder i2 which adjustably supports therein a blade [4 preferably of the hacksaw type, as suggested in Fig. 3. At its rearmost end the holder [2 is piv otally secured by a pin Hi to a crank arm l6 which is fast on a shaft i8 transversely disposed through the sides of frame iii. A brace 19 stiffens the holder on the pin.

On shaft I8 is a gear 2|] in mesh with a pinion 22, and the latter gear is fast on a shaft 24 mounted between bearings 26 and 28. The outer extremity of shaft 24 projects through the end of the frame and provides a shank portion for engagement by the chuck 30 of a power driven member 32 which preferably may consist of an electric hand drill. Operation of the drill functions to rotate pinion 22 which drives gear 29 and shaft it, thus actuating crank it and reciprocating the blade holder [2 and blade M in the supporting frame.

The blade holder is guided in its reciprocating movement by means of a link 36 which has its rear extremity pivotally secured to the side of the frame at 38, as noted in Fig. 3. The link is offset and has its forward end slidably secured to the blade holder by means of an extension 49 which is constructed with a U-support 42 adapted to engage under the bottom edge of the holder, as viewed in Fig. 3. A disc i l mounted on the extension 49 and in spaced relation thereto, cooperates with this member to form a guide channel in which the upper edge of the holder may be guided.

As will be noted in Fig. 1, the shaft i8 has secured to it on the opposite side of gear 28 a cam 48 which is arranged to bear against a rear extremity of a lever 50. The latter member is pivotally mounted on shaft 52 which extends part way through the frame. At its forward end the lever 50 is provided with a transversely disposed pin 54 which has secured thereto the lower end of a coiled spring 56. The upper end of this spring is attached to a second pin 58 supported in an upright piece Bil, in turn secured at one side of the link 36. The spring tends to hold the lever and link together with the result that as the lever is forced downwardly by the cam the link and saw are urged against the work piece. Further rotation of the cam causes the lever 58 to move upwardly and produce a rocking motion by which the saw is yieldingly held in the plane of its reciprocation.

For purposes of manually adjusting the blade holder [2 when inserting or removing the work piece W, there is provided an eccentric disc 68 mounted on a cross shaft 10 and manually operated by a wheel 12. The peripheral edge of the eccentric disc 68 is arranged to lie in contact with an under edge of link 36, as suggested in Fig. 4, with the result that the link may be raised and lowered by turning the wheel 12, thus adjusting the saw to enter or withdraw the work piece W in the work holding apparatus. The latter apparatus is located at the forward end of the frame.

and includes a jaw 14 through which is threaded a screw 76 operated by a handle 78. The screw carries a movable jaw 80 for receiving and clamping work piece W, as noted at the righthand side of Fig. 2.

In operating the device the drill 32 is connected by plugging in to a convenience outlet 82 supported at one side of the frame and furnished with suitable electrical connection to a source of power. This outlet is electrically connected to a switch 64 mounted forwardly of the frame in position to be actuated by a stop 62 fastened to extension 10. It will be seen, therefore, that the drill after being connected in the convenience outlet 82 will be operated until the out has progressed to a point at which the stop member 62 may contact and open the switch 64. In carrying out an operation, such as described, it may also be desired to place the hacksaw assembly in a fixed position, and for this purpose there has been provided a U-shaped bracket 84 which is solidly bolted to the inner side of the frame 12 in some convenient manner at a point adjacent to the convenience outlet 82 and this member may be locked up in a bench vise, or other suitable holding device.

It will be seen that I have provided an eficient, durable, and practical hacksaw mechanism which may be conveniently power driven by means of an electric hand drill and which combines, with a reciprocating movement, a unique rocking action to more satisfactorily conduct the sawing operation. It is intended that the various parts and proportions of the constituent mechanism be varied in accordance with the scope of the appended claim.

Having thus described my invention, what I desire to claim as new is:

An improved sawing tool of the class described comprising a frame, a tool holder having a sawing tool received therein, means in the frame for supporting a work piece in position to be engaged by the sawing tool, a power driven shaft transversely supported in the frame, a crank mechanism mounted on the shaft in the frame and connected directly to the tool holder for moving the tool and holder forwardly and rearwardly, a pivoted slide element constructed and arranged to guide the tool holder during its forward and rearward movement, means including a lever for urging the tool holder and. blade against the work with a force which varies in accordance with change in position of the crank mechanism, said lever having an intermediate portion pivotally mounted in the frame at a point between the tool holder and the crank mechanism and having its forward end attached to the tool holder, spring means normally operative to raise the said forward end of the lever, a cam mounted on the power driven shaft in a position to engage with an opposite end of the said shaft and constantly maintain a downwardly directed pressure on the tool holder, the cam surface of said cam being so chosen as to force the forward end of the lever downwardly with a pressure which increases during the forward stroke of the tool holder and tool and decreases during the return stroke, and the said slide element for the tool holder being pivoted in the frame and including at one end thereof a holder supporting adjustment wheel.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,211,964 Rasmussen Jan. 9, 1917 1,282,394 Driver Oct. 22, 1918 1,362,628 Kaunitz Dec. 21, 1920 1,780,439 Rasmussen Nov. 4, 1930 2,471,700 Podhajsky May 31, 1949 

